Henhy f



Sept. 2, 1924.

H. F. BICKEL ET AL METHOD 0F CONTHOLLING 'PHE RELEASE 0F AUTOMATIC AIR BRAKES Filed July 7, 1922 4 Sheets-5heet 1 Sept.4 2, 1924.

H. F. BlcKEL ET Al.

METHOD OF CONTROLLING THE RELEASE 0F AUTOMATIC AIR BRAKES Filed July 7, 1922 4 Sheets-$heet 2 Y Sept. 2. 1924. 1,506,807

H. F. BICKEL ET AL METHOD OF CONTROLLING THE RELEASE OF AUTOMATIC AIR BRAKES n' glledsduly 7, 1922 4 .Sheets-Sheet 3 Sept.' 2, 1924.

H. F. BICKEL ET AL METHOD OF CNTROLLING THE RELEASE OF AUTOMATIC AIR BRAKES 4 Sheets-Shes t 4 Filed July 7 @Houma d' Patented Sept. Il, 1924.

UNIT-ED STATES PA'riE N'TfQFFICE# HENRY Vn. mener., Ao1? Hein-FIELD,

wernngrowm Nswyonir. AssIeNon-s rTo THE New renners BLAKE COMPANY,

A CORPORATIQN oF NEW Yuma,

METHoD'oe 'co'npnotnine nELnAsEorAU'ToMATIo A1B. pennes.

V A] aplic'ntonf'ledfJiily-T, 1922. Serial No. 573,326;

To all whomr'z't 'may concern: 4 g Be it known that we, HENRY Ff Broun `und BLYTHEQI.' MINNIER, 4citizens of' the United States, residing, respectively, at Plainield-` in the county of Union and State of New Jersey,.- 'county of'Jeilelson and State of vNew York1 Methods of (.k5ntrollin,f 1,r the Release of utotomatic Air Brakes, of which' the following release This invention relate'sito a method of; controlling the vbrake releasing function o`f auto -matie airV4 brake equipment of-that type which i'nludesauxiliary reservoirs and' vtriple valves. Y

ln air brake systems of this type, it is the practice to carry inthe -main reservoir 'a pressure higher tliantliat maintained-in the brake pipe. This relatively high'main reservoir pressure olers a reserve of compressed air which is-"available to insure prompt movement ofallithe' `tripleval'ves from application position, or from lap position, to'- release-andrechargeposition.' A'

Inorde'r` to permit the engineer toconf tion is Iused toreleus" the brakes andstait the recharge of the auxiliaryv reservoirs. In ruiming position, in um reservoir 1s `"con-4 nected' to the brakeplpe 'through --t'he 'engineers valve in Suche` way that a pressure freduc'ing feed 'valve-"is interposedg-and this valve operates to'control `the"-feed'of"e1r to 'the brake pip'e,l *so that/the desired brake f pipe pressure'is maintained but is not en'r ceeded. After a brake applicationy has been-made, 4the-brakes areA releasedby movingp'the engineers brake Vvalve first'to release position i and 'later-to'l running position. The correct `nmnipulation is 'to 1 leave the valvein 4vrelease posi-tion 'only long enough `to insure the "movement of ull triple valves to releaseandrecharge position; If it'islet inV release and ,at Watertown, 1 in #the 5 unrestricted pipe;

'rpositontoo long,'tl1e reservoirs land brake pipe near the front4 ofl the train will he charged lto too high a pressure so that, when Athevalve is movedbach to runningr position, anundesii-ed reapplica'tion of the brakes on the front portion of the train will occur.

Thet-ime l'necessary to effect the movement ofall the'triple valves to release position'is dependent on the lengthof intensity of the preceding brake application, i. e., on" brake pipe volume and the reduction of brake` pipe pressure, so that it requires the exercise of considerable discretion on the part of the engineer to'esti- .NEW JERSEY, ANnmBLYri-rn .ILMmNNrEnQo-n.

the train and the' mate the time that the engineers brake valve y should be left in release position. This ditficulty is greatlyincreased in modern equipment by arily used.

length encountered require exercise of'considerable forethouglit and judgment, while lthe use of exceedingly sensitive apparatus for the purpose of securing rapid'serial ap the very long trains custom-V Thefgre'at; variations intrain' plic'ation' in Along` trainsincreases the tend` ency for reapplications to occur.

The present invention provides a method oflimiting,the` duration of the release func- Vtiouo'f the`enginee1"s brake valve, i. e., the

the brakepipe", to vcorrespondwith the length of ther train and the intensity of vthe appli- `'cationwhich,is'to liegreleesed. The method does notrquirethe exercise of discretion by thefenginer, lj'ut mayV be carried out lby' automatic devices.: i

jv'The method'is based on a recognition 'of tliefact that' thear'nount of air-'discharged through the 'equalizing discharge' valve jforming Va part of the engineers brake valve is a 'function'of the length of the train and of,V the intensity' of the application which results' from such,` discharge. The method .involves the measurement or approximate measurement of the'air discharged through the equalizngl discharge' valve, and, during -theensuing releasefunction, the 'imposition of-*a corresponding time limit on the feed of air at main reservoir pressure to the brake Thesinriplest Wayof measuring the' air discharged through the equalizing discharge valveris fto impoundthis air or a proportional -partfthereof,'"under moderate pressure; This air is thereafter released through feed otmain rescrvolr air to a restricted port in thegrelease position of the engineers valve, andV the lduration-gif outflow of this air is used to determine the duration of free flow of air from the main `reseI-voir'to-thc brake pipe.

1 While' the termination of such outflow might be used as a signal to warn the engineer to shift the engineers brake valve to is to eliminate the pressure feed valve cusl tomarily used to feed air from the main reservoir to the brake pipe running posi tion of thc engineers valve, and to substitute therefore pressure controlling valve equipped with pressurecontrolled means for holding it out of action. This pressure controllingr Vvalve is connected on its inlet vside with the main reservoir and on its discharge side both to the feed valve connection andto the main reservoir connection of the engineers brake valve. Consequent-ly,' the only communication from the main reservoir to the engineers brake valve is through this pressure controlling valve.

The equalizing discharge valve of the engineers brake valve is provided with a special discharge fitting having a restricted port leading to the atmosphere, and between the equalizlng dischar e valve and this restricted port a passage eads through a .check r valve to a small reservoir Which we call the brake pipe dischar e reservoir. This reservoir is connected yal restricted port or choke to a port in the seat of` the rotary valve of the engineers brake valve and this port is open to atmosphere in the release g running positions ofthe'engigneers brake valve. This port may conveniently be, but

I is not necessarilyg a port also controlling the holding pipe connection used with the socalled FL. T. (locomotive and tender) equipment and may be arranged toptferla retarded y release of vthe locomotive vand-.tender brakes in release position 4and a quick Y release thereof in running position.

The brake pipedischarge reservoir is also connected to the-pressure controlling, valve in such manner that the existence of pressure inthe reservoir so affects the pressurecontrolling lvalve asr tov holdv thisvalve full-y OPGU' f 1' #Thusthe reservoir is charged-in service applications; to y a lpressure dependent on the length of. the train andthe-V brake pipe pressurereduction.v 'In release the air slowly escapes through the ports above mentioned and until it has escaped the pressure controllingvalveis inoperative. The time of suchescape varies according to .the initial pressure in the reservoir and hence a proper time lfactorV may be imposed on free How and l systems of known types.

from the Vmain reservoir to thei brake pipe, by properlyl proportioning elie' restricted escape ort or choke. i

Anot ier automatic apparatus for carrying out the method involves the .use of a small air :motor forshifting tlre'r'otary valve of the engineers brake valve from release to running position, and the control of this motor' by the persistence ot'j pressure in the bralte pipe discharge reservoir described. In thissecond type of equipment, no pressure control valve is used and the ordinary feed valve Ais retained .and is connected up to the engineer-s braltevalve and the main reservoirV in the usual manner.

In the accompanying drawings are illus4 trated two specifically Adifferent types of appara-tus capable of operating according to Vthe Yabove described method. In the draw- 'fig l is a sectional view. showing the en- In this View, the engineers brake valve isV not shown as actually constructed, b ut. diagrammed in the conventional manner .familiar to thoseskilled in the art.

Fig. 2 is a fragmentary view, similar to lFig. 1, showing the engineer-s brake valve in running position. 4

Fig. 3 is a similarview showingtheengineers brake valve in service application position.

gineers brake valve in lap position'. V.

Fig. 5 is a general view Aof; the equipment carried on a locomotive showing how the parts illustratedv in Fig. 1 are preferably connected with therstraight` air brake, the L. T. equipment, pump= governor and the brake pipe.r

Fig..6 illustrates a modifiedV apparatus' also controlled by the retentiony and discharge of air int-he. brakepipc dischargereser `voir, and servingftoshift thefengineers `valve from release to running-position at Fig. 4 is a similarv vievv showing the enillustrated in Fig. 6 is connectedto air bra-ke Referring first to Figs. 1 to 4 inclus-LV@ air from the main reservoir. is` received through alpipe 11 and is delivered thereby to the inlet s idefof the pressure control valve 12. This valve is of a form familiar in the art. VIt is provided with avalve seat- 13 and a'valve member-14 which is vurged away from the seat by a coil spring 15, and which may be forced to its seat by -pressure acting on the upper side of a piston `16. Pressure is admitted to actagainst the upper side of the piston -16V throughv a needle valve 17. Thisneedle valve receives presmanso? sers Hina from the discharge connection 18 uf the 'valve 12 through a: pipe connection 19., The valve 17 is 'urged to its seat by a spring so einen is adjusme by means of t 6 tllel'ld 2l; The Valve 17 iS llr'gd in nop'ening 'direction by the pressure Huid entering 'through the pipe 19 and acting on the lower face of n 'diaphragm 22.

Consequently,- the pressnre in the pipe 1S sets revenge nre pipe 19 fig-ainsi the lou-e1- fce of the diaphrhgm 22. This results in opening the vitve l? and admitting pres sure llu'id to act on the upper face of the piston 16. thus urging he valve 14- toward its closed position. The space 'above the piston 16 is vented through n. restricted orifice, indicated at 2?), and the device as a. whole functions to maintain a substantially constant pressure in the pipe 18, and this pressure is determined by the adjustment of spring 20 by plug' '21. As stated, valves of this general type are known to those skilled in the art.

In order to suspend the regulating flinctio'n of the valve l2, a connection Q5; })'1"ovide"cl Vwhich serves to admit pressure duid at certain timos to act against the 'up per side of the diaphragm "22 and thus reinforce the action of the spring- 2(l. At such times, Vthe valve 17 is held closed 'and` since the space above the piston 16 is vented, the valve member 14 remains in its upper position away from the seat 13. Consef-ucntly, the pressure reducing' function O'E tie pressure control valve 12 is suspended.

Pressure Vctmtr'ol valve l2, unlike the feed valve customarily used in air broke systems, controls the feed of air both to the main air connection and to the ["eed connection of the engineers brake valve. 'Consequently, the pipe V18 is connected to the main air connection 25 and to the feed Valve connec- `tion 28 of the engineers brake valve 26.

Other ports visible in Fig. l are the Warning pot 29 which is open in release p'osition, 'the b-rfke pipeport- 30, the equalizing cylinder port 31, exhaust port 32, punip govei-no'r port, 33; the control reservoir port 84 and. the holdingr pipe port 35.

In release position, the rotary valve 36. operated by the usual handle 2, estublishes communication from the inain air connection (i. e. troni the space above the rotary valve) tothe brake pipe and to the 'pump governor by means of the ports 37 and 3S at the seme time' the Pieri;- 39 establishes a restricted connection-between tire control pipe and the 'exhaust port 32. Consequently, in this poeinen the locomotive and render Ybrakes ine undergoing a retarded release dxe to the escape of air from the holding' pipe 35 lo exhaust.

The equaliin", discharge piston und its eyli'cler are indieT ated generally at and the 'equal-Ming ldist-narge valve at 41. Each van@ is supplied een e special saisi; formed with a lateral exhaust port 42 ivhicl is relatively restricted; and. a Second restricted connection 43 'which leads t'o h l 'check v'n've 4% and thence to a 'closed reservoir 45 v'vhich ive call the brake pipe discharge reservoir. The equalizing reservoir is shown at 4G and is of usual construction. Leading from the brake pipe 'discharge reservoir, there is a direct connection Jy of the pipe eli' to the 'pipe 24, ivllch iis 'elinected as aleadj described, to admit pressiiie fluid against the upp'ei' side of the diaphragm 22. The pipes 47 and Q4 are both connected through a chole or restricted port 48 to the holding Vpipe 35.

In Fi which shows the device in running' position, the feed valve connection and the brake pipe connection are phl'cefd in direct communication by Ineens of the port 49 in vthe rotary,7 valve. At the saine tini'e the holding; pipe is placed in diiect and free communication with the 'ehaust port 32 by means of the 'port also forrnbd in the rotary valve.

ln Fig. fl, which s-:lroivs the service position, the equnlizing chamber is connected to exhaust by means of the port 5l in the rotarlvY valve, lvhile, in Fig. 4, which shows la position. all ports are blnnhed. It shouiii be observed iu this connection that the valve structure above described departs from former standard practice to the 'extent that the port 39 provides Por relzrded release of the engine and tender brakes in release p0- sition, and the port 50 provides for quick release oi the engine and tendcr brakes in running position. This arrangement makes it conveniently possible to vent the brake pipe discharge reservoir through the holding pipe 35.

The engineers valve has also a holding position and an emergency position, neither of which is illustrated and each of which conforms in Strict'ule and function with standard practice. They are not illustrated because neithelI directly ai'eets the 'method here involved.

In Fig. 5, We have shown the apparatus so far described as it appears when connected in un air brake system of conventional forni, and We have indicated rst of the standard apparatus formin' part of the veel khpw New Yok air brake is"f$.l'ein means 'of legends. The pjrls illu, 'ald i Figs. l to 4 'icliisie are indiatfd by the reference numerals heretofore llsd so fai' es ene-se pms er@ visible in Fig. f5. The purpose of Fig. 5 is lo indicate to 'ihs'e Skilled in the art holfv the connections to the straight air brakes, the gages, the puilp governor, the loconitive and tender equipment and the like are Iliade, and', inasnuch as the installation conforms to stindai'ld practice, @Xcept as is descr-ined in detail nieve, nbfdevlilo tailed discussion of Fig. 5 appears necessary.

Assume that the train is ruiming with the brakes released. The engineer makes a service application. Air will be rented from the brake pipe through the equalizing discharge valve 11. Part of this air flows to the atmosphere through the port 42, but a part will pass through the port 43 and check valve 44 and be confined under moderate pressure in the brake pipe discharge reservoir 45. The quantity so confined in the reservoir 45 is approximately proportional to the total amount released from the brake pipe, or at any rate it is a function of the total amount so released.

The pressure in the reservoir 4:5, acting` on the upper side of dialihragm 22, suspends the pressure reducingfunction of the valve l2. Consequently, on movement of the brake valve to release position, air flows without pressure reduction from the main reservoir pipe through valve 12, main air connection 25, and ports 3T and 30 to the brake pipe.

In release position, the port 39 in the rotary valve connects the holding pipe 35 with exhaust. This causes slow release of the locomotive and tender brakes, and allows the air in reservoir L5 to discharge through choke 48. Since choke 46 is more restricted than port 39, the rate of flow from reservoir yl5 is controlled solely by the choke.

As the pressure in the reservoir 45 falls, the pressure reducing function of the valve 12 is restored. Thereafter, both in release position and in runningl position, air will be fed from the main reservoir to the brake pipe at reduced pressure. The quantity of air confined in reservoir 45 thus imposes a time factor on the free flow of air to the brake pipe.

In this form of the device, the chief functional difference between release and running positions is that release position causes retarded release and running position quick release of the locomotive and tender brakes.

Referring now to Figs. 6 and T, a second type of mechanism operating on the same method, but acting to shift the rotary valve of the engineers bra-ke valve, will be described.

The engineers brake valve is indicated generally by the numeral 26 and is provided with port-s 39 and 50 and with a special exhaust fittingr for the equalizing discharge valve, all identical with those shown in de tail in Fig. 1. The holding pipe is indicated at 35 and is identical with that de scribed with reference to Fig. 1. The same is true of the equalizing reservoir 46, brake pipe discharge reservoir 45 and check valve 44. The choke 48 is interposed between the brake pipe discharge reservoir 45 and the holding pipe 35.

The main reservoir pipe is shown at 1l and is connected, as has been customary heretofore, to the main air connection 25 of the engineers brake valve. to supply the space above the rotary valve with air yat main reservoir pressure.. Leading from the pipe 11 is a connection through the pressure reduc ing feed valve 52 to the feed connection 28 of the engineer-s brake valve. Consequently, as has been the usual practice, the engineers valve 26, when in release position, feeds main reservoir air to the brake pipe Without reduction of pressure, and, when in running position, feeds main, reservoir air to the brake )ipe at reduced pressure.

Lea ing from the main reservoir pipe 11 is a pipe 53 and leading' from the brake pipe discharge reservoir is a pipe 54. These two pipes are connected so that the first supplies motive fluid to, and the second controis the operations of. a motor 55 Whose function is to shift the engineers brake valve from release to running position. This motor is shown in diagrammatic section in Fig. 6.

The handle 2i' of the engineer-s brake valve is provided with a sector gear 56 and this gear meshes with a rack 57 slidable longitudinally in a guideway 58. The rack 5T is provided with a longitudinal slot 59 having at its left-hand end (with refeience to Fig'. 6) a shoulder or stop 60.

Forming a part of the motor 55 is a cylinder 6l containing a piston 62. This piston is partly guided by, and abats against, the end of a sleeve 63 which is. longitudinally slidable in a ,Quideway 64. forming a part of the motor. The sleeve. 63 is urged to the right (with reference to Fig, 6) by a spring 65 and is provided with a pin 66 which runs in the slot 59 and under certain circumstances ahuts against the stop or shoulder 60 to move the rack 57 and thus shift the valve handle 2T through its connected sector gear 56.

Vthen the piston 62 is at its right-hand limit of motion, the spring; 65 shifts the sleeve 63 so that the pin 66 is moved to the right. lWith the parts in this position, the pin 66 permits the rack 5? yto move far enough to the. right to permit the engineer to move the brake valve handle 27 to release position. W'hen the sleeve 63 is in its eX- treme leftfhand position, as shown, the handle 27 cannot be moved to release position but is arrested by the stop 60 in running position. Obviously, it' the valve handle 27 is placed in release position and thereafter sufficient pressure is admitted to act against the right-hand face of piston 62, the Inovef ment of the piston 62 to the left Will shift the valve handle 27 from release to running position.

The admission of pressure Huid to act against the right face of the piston 62 and the release of such pressure are controlled all by a piston-actuated slide valve mechanism subject to the persistence of pressure in the brake pipe discharge reservoir.

Mounted on, and forming a head for, the cylinder 6 1 is a casting 67 provided with a relatively small cylinder 68 and a larger cri-axial cylinder 69 communicating therewith. The end of the cylinder 68 is close-d by a screw plug 70, and the end of the cylinder 69 is closed b-y a cap 71. This cap 71 is provided with a cylindrical spring scat 72. A coil spring 73 is mounted in the cylindrical seat 72 and bears against ay removable cap 74 provided with an air vent 75. The cylinders 68 and 69 receive a differential piston consisting of a sleeve piston 76, which Works in the cylinder, and a piston 77 which works in the cylinder G9 and is directly engaged by the spring 73.

For purpose of explanation, the directions of movementof the pistons 76 and 77 will be defined bv the terms upward"y and downward (with reference to Fig. 6).

The spring 73 urges the ditl'erentiul piston 76, 77 downward and. in this p-osition, a groove port 78, 'formed in the Walls off cylinder 69, equalizes the pressure on the opposite sides of the piston head 7 7'. Since the space at the upper side of the piston head 77 is vented to the atmosphere through the port 75, the effect of opening' the groove port 78 is to establish atmospheric pressure in the annular space below the piston head 77. The piston 76 is Aformed with a tubular body which establishes communication from the space below the piston to the ports, 79. In the lowest position of the differential piston 76, 77, these ports are closed, but, in a, slightly higher position of the differential piston., they communicate with an annular groove port 80 and in conjunction with it establish a. connection from the Space below the piston 7 6 to the Iannular space below the piston 77. The pipe 54, which leads from the brake pipe discharge reservoir, is connected to the space below the piston 76.

Formed on the casting 67 is a slide valve seat 81 which is housed by a cap 82 form ing a pressure chamber 83 to which main reservoir air entering through the pipe 53 is communicated by a port 84. VThe valve seat 81 is formed with a port 8.5, leading 'to the cylinder 61, and with an exhaust port 86, leading to the atmosphere. A slide valve 87 is mounted on the seat 81'and is held to its seat by a leaf spring 88. This valve is connected by a pin 89 with the piston 7G.

The pin 89 is seated in a web 9() extending across the bore of the tubular piston 7 6, but not obstructing the same, there being as heretofore explained a space for the free passage ot air through the bore ol the piston 7G around the web 9() to ports 79.

The slide valve 87 is provided With an admission port 91 which, in the lower position of the valve 81, connects the pressure space 83 with the port S5 and hence with the cylinder (il. The valve 81 is further provided with an exhaust port 92 which, in the upper position ol the` valve 81, connects the port S5 and hence the cylinder G1 with the exhaust port 8G. Y

The operation of the device illustrated in Figs. (i und 7 may now be outlined. Suppose that the train is running with the brakes released, and that the engineer makes a serv ice application iu the usual manner. This involves the release of air through the equalizing discharge valve. A portion of this air passes the check valve 44 and is confined in the brake pipe discharge reservoir 45. Since the'brake pipe discharge reservoir is connected by the pipe 54 to the lower end of the cylinder 68, the pressure acting against the lower side of the piston 76 will gradually rise as the reservoir 45 is charged. The effcct of this pressure is gradually to overpou'cr the spring 73 so that the piston structure 76, 77 l'icgins to move upward. Before it has moved far enough to change the relation of the ports of the valve 87, the piston head 77 will oveutravel the groove port 78, and the ports 79 will reach the annular port 80.

The ell'ect of the closing of the port 78 and the opening of the ports 79 is to admit the brake pipe discharge reservoir pressure against the annular lower surface of the piston head 77, greatly increasing the elfective area against which this pressure acts and, consequently, causing the sudden movement of the differential piston 76, 7 7 to its extreme upward position. This movement shifts the valve 87 so that the supply of pressure fluid to cylinder 61 is out olf and the cylinder (l1 is connected to atmosphere by means of the exhaust port 92.

The spring' (l5 then moves the sleeve 63 and with it the piston 62 to their right-hand positions, This moves the pin 66 to its ex treme right-hand position so that the valve handle 27 may be moved to release position. The parts remain in this condition until after the engineer has commenced to release the brakes. To release the brakes, lie moves the valve handle 2 7 to release position. In thi position,- tlie main reservoir air flows freely to the brake pipe and, at the same time, the port 39 eil'ects a, retarded release of the locomotive and tender brakes, and a slon7 discharge ot air from the brake pipe discharge reservoir 45 through the choke 48.

As the brake pipe discharge reservoir pressure drops, a point Will be reached at which the spring 7 3 begins to move the piston structure 78, 77 downward. A slight movement of this piston structure opens the port 78 and closes the ports 79, causing a sudden reduction in the effective area against which the brake pipe discharge reservoir pressure uio lll)

lto the lett, overpowering the spring and shifting the brake valve handle 27 to running position through the action of the pin 16, shoulder 60, rack 5T and sector gear 56.

The mechanisms above described are merely two ot' many automatic mechanisms which mayY be devised to operate according to the method forming the subject matter of the present application. The claims of this application are restricted to the method, the claims to the apparatus being presented in related applications as follows: Serial No. 597,967, tiled October 30, 1922. Serial No. (iti-5.660., tiled Sept. 29th, 1923.

The broader method claims of the present application are not restricted to the use ot automatic means for terminating' the release function of the engineers brake Valve, but are drawn broadly to the idea ot' measuring the air released trom the brake pipe and thereafter using this measurementto determine the duration of the release function of the engineers valve. Such determination ma?.7 involve merely the giving of a proper indication to the engineer of the duration of the proper release period and may, theretore. require the attention and cooperation oi the engineer, or may be made entirely automatic.

That is claimed isz-- l. That method of controlling the release of automatic air brakes, including a brake pipe and a main reservoir normally charged to a pressure higher than brake pipe pressure, which consists in measuring the quanti y ot air discharged from the brake pipe in producing a brake application, and thereafter, during the releasing ot said application, limiting the duration of ioW ot' air at main reservoir pressure to the brake pipe according' to such measurement.

i2. T hat method ot' controlling the release of automatic air brakes. including a brake pipe and a main reservoir normally charged to a pressure higher than brake pipe pressure, which consists in confining under pressure air released from the brake pipe in producing a brake application, the quantity of air so conlined being a, function of the total quantity of air released from the brake pipe, and thereafter, during the releasing of such application, permitting the gradual escape of the coniined air and limiting the duration ot' ilow of air at main reservoir pressure to the brake pipe according to the duration of such escape.

3, That method of controlling the release of automatic air brakes, including a brake pipe and a main reservoir normally charged to a pressure higher than brake pipe pressure, which consists in confining under pressure air released from the brake pipe in producing a brake application, the quantity ol air so conlined being a function of the total quantity of air released from the brake pipe, and thereafter, during the releasing of such application, permitting the escape of said coniined air at a controlled rate, While subjecting the duration of unrestricted feed from main reservoir to brake pipe to control by such escape.

4. That method of controlling the release of automatic air brakes, including a brake pipe and a main reservoir normally charged to a higher pressure than the brake pipe, which consists in automatically limiting the duration ot free flow of air from main reservoir to brake pipe to eilect release of an application, according to the quantity of air previously released from the train pipe to eliect such application.

That. method of controlling the release ot' automatic air brakes, including a brake pipe, a main reservoir normally charged to higher pressure and controlling valve means having a release condition in Which main reservoir air is fed Without pressure reduction to the brake pipe, and a running condition in which main reservoir air is ted at reduced pressure to the brake pipe,

which consists in manually establishing such release condition, and then automatically converting to running condition after a time interval imposed by the quantity of air discharged from the brake pipe to etfect the application undergoing release.

In testimony whereof We have signed our names to this specification.

HENRY F. BICKEL. BLYTHE J. MINNIER. 

